Apple Watch Series 12 and Ultra 4 Owners Report Skin Irritation Under the Sensor

Some owners of the Apple Watch Series 12 and Apple Watch Ultra 4 say the new watches are irritating their skin, with a burning feeling and redness under the sensor on the back. Apple has made no statement about these models, and nobody has confirmed a cause or how many people are affected (MacRumors).

What owners are reporting

MacRumors reported the complaints on October 7, drawing on a thread on its own forums and a discussion on Reddit's r/AppleWatch. The symptoms described are a burning sensation and redness on the wrist where the sensor array touches the skin. A few owners say they returned their watches. Others say the irritation eased after an adjustment period, or after cleaning the back of the watch and the band thoroughly, though some say neither helped (MacTrast, Notebookcheck).

The reports are anecdotal. MacRumors does not say how many people are affected, and online threads tend to collect complaints from the small share of owners who have a problem, not a sample of all buyers. The number of affected watches cannot be judged from these posts.

Is the sensor to blame?

Some owners suspect the heart rate sensor, which takes readings every five seconds on these models. MacRumors lists several hardware changes that could be relevant:

Change on Series 12 and Ultra 4	Status as a cause
Heart rate readings every five seconds	Owner theory, unconfirmed
Larger ECG electrode surface	Unknown
Photodiodes arranged in a ring	Unknown
Larger green LEDs	Unknown

MacRumors is clear that it is unknown whether any of these changes causes the problem, and Apple has not confirmed a sensor-related issue (PhoneArena). Complaints about wrist irritation go back to the original Apple Watch, so the reports are not unique to these models.

What Apple's support page says

Apple has no statement specific to these watches. Its general support document on skin irritation attributes reactions to allergies, environmental factors and prolonged exposure to irritants such as soap and sweat trapped under the watch. Fit matters too: a band that is too tight can irritate skin, and one that is too loose can rub.

On materials, Apple says the nickel in Apple Watch cases, some bands and magnets is below the strict limits of the European REACH regulation, and that it considers nickel exposure unlikely to be a problem, though people sensitive to nickel should be aware of it. It also says trace amounts of acrylates and methacrylates from adhesives are present in some cases and bands, and that these parts are designed not to touch the skin directly.

Apple's guidance	What it says
Cleanliness	Keep the watch, bands and skin clean and dry, especially after workouts or exposure to sweat, soap, sunscreen or lotion
Fit	Snug but comfortable, with the back of the watch touching the skin, worn above the wrist bone
Loose check	Shake your wrist and turn your palm up, and tighten the band if the watch loses skin contact
After exercise	Loosen the band if you tightened it for a workout
Symptoms	If you notice redness, swelling or itching, consult a physician before wearing the watch again

What owners can do

Apple's advice applies whatever the cause. Check the fit, keep the contact area clean and dry, and stop wearing the watch if the skin is red, swollen or itchy, then speak to a doctor before putting it back on. Apple's page also says leather, FineWoven, stainless steel link, Milanese and Hermès knit bands are not water resistant and should not be worn in water or during workouts, which matters if irritation might be linked to sweat trapped under a band.

Owners who believe their watch is at fault can report it to Apple Support. Apple has not said whether it is treating these cases as a hardware issue, and return terms vary by market and retailer.

What it means for buyers

For someone deciding whether to buy, the reports are a caution and not a verdict. The evidence so far is forum and Reddit posts, an untested theory and no confirmation from Apple. Anyone with known skin sensitivities may want to check the return terms where they buy.

What to watch next

Watch for an Apple statement or support note that names the Series 12 and Ultra 4, whether complaints grow or fade over the coming weeks, and any software update that changes how often the heart rate sensor samples.

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